In a method of the above-mentioned kind the web server provides data to the data processing device, which the latter has requested before, by the web server either reading out the requested data from a memory of the data carrier or, if the data are not stored in the memory, obtaining them from a data provision device, e.g. from a server computer in the Internet. The data processing device here for example can be a personal computer (PC), for which the data carrier acts as a so-called proxy. That means, vis-à-vis an application on the PC, e.g. vis-à-vis a web browser installed on the PC, the data carrier appears as a data supplier—i.e. as a data server—, but vis-à-vis an Internet server computer as a data recipient—i.e. as a data client. A data carrier used in such a way normally comprises an Internet protocol stack and can serve a user for example as an authentication gateway, e.g. for online banking applications or the like.
Portable data carriers, e.g. chip cards, have very limited resources regarding storage capacity. This concerns both volatile buffer memory or main memory and non-volatile memory, for example in the form of flash memories or the like. Due to the limited buffer memory, a data communication between the data carrier and an Internet server computer, for the purpose of obtaining data which are not available to the data carrier and are to be provided to the web browser on the PC, must be divided into relatively small data packets. When the response times of the Internet server computer are high, for example due to high data traffic in the Internet at a certain time of the day or a generally high load on the relevant Internet server computer, the requested data can thus be provided only very slowly to the web browser.
In the above-described scenario, the data carrier cannot resort to a strategy known from normal Internet usage without employment of an intermediary data carrier, according to which a web browser stores data, once they are obtained, on the hard disk of the PC, optionally in accordance with a user setting, so as to be able to read out these data directly from the hard disk for a future use without having to contact an Internet server computer for this purpose. Such an anticipatory storing is also referred to as “to cache”, the corresponding memory “cache memory”. But in the described scenario, the above-described portable data carrier cannot take on the same role vis-à-vis the Internet server computer as the web browser equipped with a cache memory in usual Internet usage, because the data carrier has too few resources at its disposal, in particular too few non-volatile storage capacity in order to realize the known strategy of storing data once they are obtained.
WO 00/65800 A1 describes a system which comprises a portable device, for example a handheld or a mobile radio terminal, having a web browser which contactlessly exchanges data with a server. The web browser stores all data, once they are obtained from the server, for a possible future use. When the memory space provided therefor is exhausted, stored data are deleted according to known strategies, e.g. the FIFO strategy (“first-in-first-out”). A passing on of the data obtained from the server by the portable device to a further data processing device is not disclosed in WO 00/65800 A1.
In WO 03/094474 A1 there is described a method for operating a mobile radio terminal. Therein, an application of the mobile radio terminal, e.g. a web browser, checks whether data received from a server of the mobile network operator comprise a store instruction, and then it stores only such data for a future use which comprise such a store instruction. In this way the mobile network operator can determine which data are stored on the mobile radio terminal. WO 03/094474, too, describes no passing on of the data obtained from the server to a third instance.
DE 103 17 147 A1 discloses a chip card with a flash memory and a cache memory in the form of a non-volatile RAM memory. With the help of a control unit there is created, by means of the flash memory and of the non-volatile cache memory, a memory system with non-volatile memory that can be updated very quickly word by word. A use of the chip card for the purpose of data communication between various units, e.g. between a PC and an Internet server, is not disclosed in DE 103 17 147 A1.